This thesis deals with nonlinearities in the radiation field relevant to laser fusion. To describe the radiation field we use the photon transport theory which we believe, has some advantages: mathematical simplicity, natural separation of microscopic versus macroscopic nonlinearities, treatment of matter dynamics to any desired level of approximation, among others. Since our only concern here is in microscopic nonlinearities, we describe matter (plasma or neutral media) as in thermal equilibrium. We investigate stimulated scattering by plasmas (stimulated Brillouin scattering, stimulated Raman scattering) as well as by neutral media (stimulated Brillouin scattering). We also discuss the nonlinear inverse bremsstrahlung absorption in plasmas and some other nonlinearities relevant to high power laser amplifiers (nonlinear index of refraction, nonlinear absorption, nonlinear gain). We briefly discuss what appears to be an unnoted mechanism for nonlinear gain saturation (especially in CO(,2) laser amplifiers)--intensity broadening of the upper lasing level.Ph.D.Nuclear engineeringEnergyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/157926/1/8025693.pd
